Generally, as a brake disc for a two-wheeled motor vehicle, there have been widely put to practical use a brake disc that is provided with a mounting section to be mounted to a wheel and a slide section making sliding contact with a brake pad and is formed by press molding a single piece of metal plate, and a so-called floating brake disc that is provided with an annular slide disc having a slide section against which a brake pad is pressed, a hub disc which is attached to the inside of the slide disc, and a plurality of connectors which connects the brake disc and the hub disc to each other in a floating state.
Further, there has also been widely adopted a brake disc including a plurality of weight reduction holes which is formed in a slide section in a predetermined arrangement for the purpose of total weight reduction, improvement of the heat release property in the slide section, cleaning of a brake pad, and the like (see Patent Documents 1 and 2, for example).
Further, there has also been proposed and put to practical use a brake disc including one or more grooves which are formed in a slide section making sliding contact with a brake pad in order to prevent generation of noise during braking (see Patent Documents 3 to 5, for example).